• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.294-298
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• 2003

In this paper, the modeling and design of high-Q multilayer passives have been investigated, and multilayer diplexer for GSM/DCS applications has been designed and fabricated using the passives. To minimize the system, the configuration of a multilayer inductor has involved a square spiral structure. Modeling of a multilayer inductor was performed by the subsystems of distributed components, and using the modeling the optimal structures of the high-Q multilayer inductor could be designed by analyzing parasitics and couplings which affect their frequency characteristics. Multilayer diplexer for GSM/DCS application has been designed and fabricated using LTCC technology. LPF for GSM band had the passband insertion loss of less than 0.55 dB, the return loss of more than 12 dB, and the isolation level of more than 26 dB by locating attenuation pole at 1800 MHz. HPF for DCS band had the passband insertion loss of less than 0.82 dB, the return loss of more than 11 dB, and the isolation level of more than 38 dB by locating attenuation pole at 930 MHz.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.89-95
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• 2005

In this paper, a quad-band antenna for GSM/GPS/DCS/US-PCS handsets is proposed. The proposed antenna is low-profile for mounting in limited inner space of a handset. It consists of three open points with quarter wave length for multi-band operation. The ground plane below the patch is removed for wide-bandwidth without the variation of antenna size and the slot is added at the center of the patch for convenient matching in high frequency band. It provides a enough bandwidth within VSWR 3:1 at all bands. In addition, the measured peak gains are between -2.19 and 2.09 in anechoic chamber (10m$\times$6m$\times$4m).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.4
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• pp.65-70
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• 2011

In this paper, we designed and implemented a PIFA(Planer Inverted F Antenna) and IFA(Inverted F Antenna) hybrid antenna for the data communication terminal such as smart phone. Studied hybrid antenna has multi-band characteristics by the simultaneous operation both PIFA and IFA under a feeding structure. VSWR measurement of implemented antenna was satisfied 3:1 over GSM900/USPCS/WCDMA band. Measured average gains and efficiencies were -2.19~-3.63 dBi and 43.31~60.33 % for the GSM900 band, and -2.16~-10.67 dBi and 8.56~60.78 % for the USPCS/WCDMA band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1259-1268
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• 2010

In this paper, we presented a new LC prototype synthesis method for the multi-band filter. For synthesis a multi-band filter with the required frequency response, we proposed the diagram of poles and zeros, also, we proposed the optimization process for finding the combination of optimized poles and zeros. From the transfer and reflection functions calculated from poles and zeros, we performed the quasi-elliptic LC prototype synthesis of multi-band filter. Using the proposed LC prototype synthesis method of multi-band filter, dual-band filter operating at GSM(880~960 MHz) and ISM(2,400~2,500 MHz) and triple-band filter operating at GSM(880~960 MHz) and ISM(2,400~2,500, 5,725~5,850 MHz) were designed and fabricated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.737-743
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• 2011

In this paper, we designed and implemented a Monopole+IFA(Inverted F Antenna) hybrid antenna using the coupled feeding structure for the all band mobile phone. Studied antenna has wide band characteristics by the simultaneous operation both monopole and IFA under the coupled feeding structure. An antenna has designed PCB embedded type without antenna carrier component for the low in cost. Implemented antenna has within 2.5:1 for VSWR under LTE/CDMA/GSM900/DCS/USPCS/WCDMA/WiBro/WiFi in all band for the mobile services Measured average gains and efficiencies were -3.98~-0.09 dBi and 40.03~97.99 % for the LTE, CDMA, GSM900 band, and -3.90~-1.01 dBi and 40.70~79.31 % for the DCS, USPCS, WCDMA, WiBro, WiFi band. It's shown that studied antenna can be applied to all band mobile phone antenna including LTE.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.288-297
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• 2007

The novel internal monopole chip antenna of penta-band operation for GSM850/GSM900/DCS/USPCS/WCDMA bands for mobile phones is proposed. This antenna occupies a small volume $8\times3.2\times20mm^3$ and is suitable to be embedded in a mobile phone as an internal antenna. The minimization of the proposed antenna was realized by using spiral line structure and meander line structure on FR-4 of dielectric$(\varepsilon_r=4.4)$. The designed antenna has the wide-band operation in the upper band by overlapping high order resonances. The measured bandwidth of this antenna (VSWR>3) is 150MHz$(1,030\sim1,180\;MHz)$ in the lower band operation and 650 MHz$(1,760\sim2,410\;MHz)$ in higher band operation. The measured radiation efficiency within bandwidth(VSWR 3:1) is over 50 %. The antenna has been designed by a commercial software HFSS.

• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.119-123
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• 2017

This paper presents a unique and miniaturized dual-band coplanar waveguide (CPW-fed) antenna for modern wireless communication. A new technique of using a modified ground structure (MGS) and frequency shifting strips (FSS) has been employed in the design to achieve dual-frequency operation. The proposed antenna generates two separate impedance bandwidths and covers the minimum required frequency bands of GSM 1800, GSM 1900, and Wi-Fi/WLAN 5 GHz. The proposed antenna is relatively small ($17{\times}20mm^2$) and operates over frequency ranges 1.51~2.06 and 4.43~6.70 GHz. The designed antenna was simulated using Ansoft HFSS, a FEM based simulator, and antenna characteristics, such as reflection coefficient, gain, radiation efficiency, radiation pattern, impedance bandwidth, VSWR, surface current, and electric field distributions, are reported in this paper. The effect of the antenna's key structural parameters on its performance is also analyzed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1179-1185
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• 2005

In this paper, novel internal antenna with its controllable resonant frequency is presented for triple-band or over mobile handsets. The operating range can include GSM(880${\~}$960 MHz), GPS(1,575$\pm$10 MHz), DCS(1,710${\~}$1,880 MHz), US-PCS(1,850${\~}$l,990 MHz), and W-CDMA(1,920${\~}$2,170 MHz). The proposed antenna is realized by combination of a half wavelength loaded line and a shorted monopole. A single shorting and feeding points are used and they are common to both antenna structures. By controlling a value of lumped inductance element between shorting point and ground plane, the antenna provides enough bandwidth to cover DCS, US-PCS, and W-CDMA respectively. When these higher bands are controlled by the values of inductance, resonant characteristics in GSM and GPS bands are maintained. In this work, maximum value of the inductor is limited within 3.3 nH to mitigate gain degradation from frequency tuning. As a result, measured maximum gain of antenna is -0.58${\~}$-0.30 dBi in the GSM band, -0.57${\~}$0.43 dBi in the GPS band and 0.38${\~}$1.15 dBi in the DCS/US-PCS/W-CDMA band. In higher band, the proposed antenna is certified that resonant frequency of about 240 MHz can be effectively controlled within gain variation of about 0.77 dB by simulation and measurement.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.3
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• pp.78-86
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• 2013

A hybrid MIMO(Multi Input Multi Output) antenna which is operating both a monopole and a IFA(Inverted F Antenna) is designed. It's applied Vlade(Vertical lade) technique to reduce antenna space, and a diagonally fed MIMO antenna is designed on the bare board for the data communication. Return losses due to variables of antenna length are simulated for the design. Antenna for the hexa-frequency band of LTE700, CDMA, GSM, DCS, PCS and WCDMA is designed and implemented. This antenna is satisfied 3:1 VSWR over the whole design band by the measurement of return loss. And average gains and efficiencies were -3.67 ~ -2.53dBi and 42.06 ~ 55.84% for LTE700/CDMA/GSM frequency band, -3.27 ~ -1.21dBi and 47.08 ~ 75.6% for DCS/PCS/WCDMA frequency band. The isolation between 2 antenna that is one of important factors for the MIMO system was measured good performance as -8.14 ~ -25.77dB over the whole service band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1455-1461
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• 2008

We implemented a subminiature internal antenna that is around 1 cc volume for the mobile phone. The fundamental type of studied antenna is IFA(Inverted F Antenna), and this antenna is designed to be improved efficiency and gain due to minimum current cancellation by the avoidance of multiple bending pattern. For the implementation of multiple band, helix is applied to compensate for short antenna length for low frequency band, and a 3 dimensional pattern is used for high frequency band. We made two kinds of 3D structure antenna. One is a 1 cc volume antenna for GSM/DCS band on the bare board set, and the other is a 1.5 cc volume for the GSM/USPCS mobile phone set. Measurements showed good gain performance that average gain of two antenna on each band are $-3.46{\sim}-0.45\;dBi$ and $-4.80{\sim}-3.29\;dBi$ respectively.